In semiconductor technology, higher-k materials such as ZrO2 and HfO2 are being implemented in order to achieve lower effective oxide thickness without compromising the ability to prevent dopant migration between the gate and channel region. A gate dielectric layer consisting of a high-k dielectric film with a thickness of less than 20 angstroms is difficult to control by a CVD technique which usually has a relatively fast deposition rate. Accordingly, atomic layer deposition (ALD) has been proposed to provide a more controllable deposition rate.
While a variety of techniques to use ALD to form a film have been generally adequate for their intended purposes, they have not been entirely satisfactory in every aspect.